Distance-type product-responsive relay



s. GOLDSBOROUGH DISTANCE-TYPE PRODUCT-RESPONSIVE RELAY Aug. 19, 1947.

Filed Feb. 16, 1945 IIIIl-llll II.

3 H ,6 m W 9. n m .3 k fi my H n i n Fw .---L m? ir Fiji INVENTOR Shirley L. G 0 ids araoyfi,

WITNESSES:

ATTORNEY Patented Aug. 19, 1947 DISTANCE-TYPE PRODUCT-RESPONSIVE RELAY Shirley L. Goldsborough, Basking Ridge, N. J assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application February 16, 1945, Serial No. 578,158

2 Claims.

My invention relates to a new wattmetric type of adjustable-characteristic modified impedance relay for protecting alternating-current lines against faults.

The principal object is to provide means for exciting the two windings of a product-responsive or wattmetrie relay so as to be adjustably responsive to the vector sum of a line-current and a line-voltage, in each case, with means for varying the relative phase-angles and the magnitudes of the several responses in such manner as to provide independent adjustments of the several characteristics of the response-circle.

A further object is to provide a modified-impedance relay having means for independently varying the slope of its center-line, or line joining the center of the circle and the origin of the rectangular coordinates of line-resistance and line-reactance, and also independently adjusting the two intercepts of the circle on the centerline.

With the foregoing and other objects in view, my invention consists in the combinations, systems, parts and methods hereinafter described and claimed, and illustrated in the accompanying drawing, wherein Fig. 1 is a diagrammatic view of circuits and apparatus embodying my invention in an illustrative form of embodiment utilizing a cosinetype wattmetric or directional relay-element;

Fig. 2 is a similar view of a modified form of embodiment utilizing a sine-type wattmetric or directional relay-element, and

Fig. 3 is a curve-diagram illustrating a typical response-circle and showing the characteristics which can be independently adjusted in accordance with my invention.

My present invention is of general application to any wattmetrie or product-responsive relay, whether of the sine-type, or cosine-type, or any intermediate type. Such a relay utilizes two alternating magnetic fluxes 4n and 2 having a phase-angle 450 between them, and it develops a maximum torque at a certain characteristic phase-angle r between said fluxes. For a cosineresponsive element, 4 is for a sine-element r=90; for a 45-element, r=4=5, etc. The torque of such a wattmetric element is therefore In order to obtain a distance-response or an impedance-response, I make both of these fluxes responsive to both a line-derived voltage E and a line-derived current I A 0. In order to adjust the relay response-characteristics, in the most gen- 2 eral case, I provide means for adjusting both the phase and the magnitude of each of the responses. The two fluxes may be written The total relay-torque is the sum of the products of the different pairs of terms, each multiplied by cos (0-r), where 0 is the angle be-.

tween the two terms being multiplied. The torque is therefore The slope of the line connecting the center to the origin is 3 4 The displacement of the center from the nected in series, and are energized from. a potenorigin is tial transformer I through a variable phaseshifter 8 and a fixed phase-controlling induct- D=\/R2+X2: ance 9. The potential transformer T derives an WW 1 5 alternating relaying-voltage E from the line 5 in WT response to the line-voltage. x

Any suitable phase-shifter 8 may be lltlllZEd,

The radius of the circle is for changing the phase-angle, without substantially changing the magnitude, of the voltage im- /n +n; 2 S U (12) l0 pressed thereon. The particular phase-shifter cos shown at 8 in Fig. l is one which is described The intercepts of the circle on the center-axis, and claimed in an application of H J. Carlin,

the center-axis being the line connecting the Serial No. 583,926, filed March 21, 1945, and ascenter and the origin, are signed to the Westinghouse Electric Corporation.

Equations 8 to 14 show that the characteristics It is capable of effecting a phase-shift of between i of the response-circle of a wattmetric relay, ener- 0 and some plus or minus, through a regized as shown in Equations 2 and 3, are very versing-switch II. It comprises amutual reactor complex quantities, when expressed in terms of 5 Mi having a primary winding I3 in series with the controllable variables, m, n, S, U and V. the voltage-source E, and a secondary inding In accordance with my present invention, how- I4 connected across the voltage-source E through ever, I have discovered that very simple, practia large variable resistor R1. cally usable relations may be obtained by making The fixed inductance 9 is included in the po-- the angle U equal the angle i in the element at 30 tential-coil circuit in order to introduce a fixed which the maximum torque occurs, and by makphase-shift of approximately 90 in the potening the angle V always equal 180+U. Expressed i tial-coil current. Thus, the two elements 8 and 9 in equations, these essential conditions are together provide a phase-shift that can be varied U:T (15) between S=fi0 and 8:120", using the terminob VZ18OO+T (16) og of Equations 2A and 3A.

The apparatus shown in Fig. 1 thus provides By equating the torque-equ tion 3 Zero, means whereby the center-line slope S of Equa-' in Ord r 60 as e ta t e a a -p e 8 tion 10A may-be varied, by means of the variable eilicients g and become im a er a insofar as phase-shifter 8, withoutvarying the center-line the S E a position of t resp se-circle are 40 intercepts Di and D2. The major intercept Di concerned. may be'varied, substantially independently of the Th relay-fl es m y h n be exp s minor intercept D2 or the slope So, by adjustin 1:ELS mILO (2A) the tap while the minor intercept maybe 3 (WZEL (SW25?) +7114 (3A) similarly independently ad usted by adiusting the apm. The center-1111a Slope becomes The relay W in Fig. 1 is intendedto be symbolic 3 :3 10 of any means for providing a torque which is proportional to the vector sum of the current mi and voltage E 4 S in the field coils IR and ER, times (13A) the vector sum of the current nl and voltage E 48 (133) in the polarizing coils I0 and E0, times the cosine The center-line intercepts become Fig. 1 shows the application of these principles of the g e between them, or, in general, times to a wattmetric (or product-responsive) relay- 1 any functlon 0f the angle between themelement W of the cosine type, that is, one in means may also used. which the torque is a maximum when the two For t i i 2 illustrates'the apphcatlon alternating quantities to be multiplied are in Of y lnvelfltlonv to a sine-type Wattrnetric relay phase with each other, that is, when 0. The W1 having two Voltage-type windings and field windings of the directional or impedance for developing a torque proportionalto the prodelement W in 1 somprise a field potential not of the energizing-currents in said windings coil ER and afield current coil Is. The polarizalid r times e ne 0f the phase-angle ing windings similarlycomprise a polarizing 130- between the impressed Voltages- The 1lelay W1 tential coil E0 and a polarizing current coil I0. has the relay-Contacts 3! which @1039 when the The relay element Walso has relay-contacts 3 relay responds for controlling a protective-relay circuit 4 for In 2 the excitation 1'5 ShOWnHS being i protecting an alternating current line 5 response to current-compensated voltages. .The

A line-current transformer 6 derives an altersame source of the adjustable-phase hating relaying-current i from the line in re- Voltage E 1s shownmpigrzrasin Fig. M

sponse to the line-current and supplies this curh ase hifters 8 n 9. Th 1' rent to two variable-ratio auxiliary transformers p s a d e cur ent response m F 2, i b TR n To having amiable taps m and n, sienna; $33551?aitwfiiiipid iiitifiiifiii spectively, for supplying the separately adjustable prising the potential transformer 7, and the able resistors Rm and Rn, connected in-twocurrents ml and iii to the current-coils In and Io, branch-circuits in series with E 4 S, as shown at l respectively. 7 2| and 22,- respectively, for energizingtherelaw The two potential coils ER and E0 are concoils i and- 2, respectively; The line-currentlis circulated through the resistors Rn and Rm to produce the voltage-drops +Rnl and Rml, respectively.

In Fig. 2, since the illustrated directional element W is a sine-relay, the exciting-currents in the two coils 4n and 2 must be dephased by the angle 90 when the same voltage is impressed on each. To this end, I have shown a capacitor C2 in series with the coil 2, the relative numbers of turns of the two coils 1 and 2 being properly chosen so that the desired flux-magnitudes are obtained.

From the circuit in Fig. 2, it is evident that the flux l=ELS-RmIL9 (2B) is produced by the coil or, while the other coil 2 produces the flux 2=(E4S+R1J40) 490 (33) corresponding to Equations 2A and 3A when the relay-angle 51:90.

Thus, in Fig. 2, the slope of the center-line is controlled by adjusting the phase-shifter 8, while the center-line intercepts D1 and D2 are independently controlled by adjusting Rn and Rm, respectively.

In Fig. 3, I have shown a typical responsecircle 30, having a center C at (R0, X0) a centerdisplacement and center-axis CO=D0, a centeraxis slope So, and center-axis intercepts D1 and D2. The circle-radius is also indicated at Q0.

It will be noted that the angle S and the magnitudes m and n are relative values. The angle S refers to the angle by which the voltage-responsive excitation-component leads the current-responsive component, or the angle by which the latter lags the former, at unity power-factor. The coefficients m and n refer to the ratio of the relative magnitudes of current-response to voltageresponse, or vice versa. The relations are general.

While I have illustrated my invention in two illustrative forms of embodiment, I wish it to be understood that the invention is susceptible of considerable variation in its forms of embodiment, and I desire that the appended claims shall be accorded the broadest interpretation consistent with their language.

'I claim as my invention:

1. An adjustable distance-type product-responsive relay having two diverse cooperating alternating magnetic fluxes, means for so utilizing said fluxes as to produce a torque in response to the product of said fluxes, multiplied by cos (0-r), where 0 is the angle between said two cooperating fluxes, and r is the characteristic phase-angle of the relay, and two diverse flux-producing means for producing the respective fluxes, characterized by each of said fluxproducing means comprising means for producing a voltage-responsive excitation-component in response to a line-derived voltage, means for producing a current-responsive excitation-component in response to a line-derived current, a common phase-shifter means for causing substantially the same phase-angle S to exist between the two excitation-components of each of said cooperating fluxes at unity power-factor, said phase-shifter means being adjustable to vary said phase-angle S without substantially varying the relative magnitudes of said components, said flux-producing means including circuit-connection means for causing a phase-angle of substantially ar to exist between the two voltage-responsive excitation-components, and also between the two current-responsive excitation-components, of the two cooperating fluxes, and separate magnitude-adjusting means, one for each of said cooperating fluxes, for substantially independently adjusting the ratio of the relative magnitudes of current-response to voltage-response of each of said cooperative fluxes without substantially varying said phase-angle adjustments.

2. An adjustable distance-type product-responsive relay having two diverse cooperating alternating magnetic fluxes, means for so utilizing said fluxes as to produce a torque in response to the product of said fluxes, multiplied by cos (0r), where u is the angle between said two cooperating fluxes, and r is the characteristic phase-angle of the relay, and two diverse flux-producing means for producing the respective fluxes, characterized by each of said fluxproducing means comprising means for producing a voltage-responsive excitation-component in response to a line-derived voltage, means for producing a current-responsive excitation-component in response to a line-derived current, a common phase-shifter means for causing substantially the same phase-angle S to exist between the two excitation-components of each of said cooperating fluxes at unity power-factor, said phase-shifter means being adjustable to Vary said phase-angle S without substantially varying the relative magnitudes of said components, said flux-producing means including circuit-connection means for causing a phase-angle of substantially r to exist between the two voltage-respom sive excitation-components, and also between the two current-responsive excitation-components, of the two cooperating fluxes, and separate magnitude-adjusting means, one for each of said cooperating fluxes, for substantially independently adjusting the magnitudes of the currentresponses of the respective fluxes without substantially varyin the phase-angle adjustments.

SHIRLEY L. GOLDSBOROUGH.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,000,803 W arrington May 7, 1935 2,115,597 Traver Apr. 26, 1938 2,393,983 Goldsborough Feb. 5, 1946 FOREIGN PATENTS Number Country Date 589,153 Germany Nov. 16, 1933 188,426 Switzerland Nov. 12, 1934 

